Phonograph attachment



Oct. 1929- u. J. BURKE 1,732,459

PHONOGRAPH ATTACHMENT Filed July 15 1926 Wa M Zy QMKZQMA 15.

Patented Oct. 22, 1929 UNITED STATES ULYSSES J. BURKE, OF DES MOINES, IOWA PHONOGRAPH Application filed July 13,

This invention relates to improvements in phonographs, and particularly to that part of the phonograph where the mechanical vibrations of the stylus are converted into sound vibrations, and to the conducting of said sound vibrations to the tone arm of the sound amplifier device.

The object of my invention is to improve the mechanism of a phonograph which con- 1e verts the mechanical vibrations of the stylus to sound vibrations, whereby the harshness of the sound tones will be greatly modified, and whereby clear and more distinct tones may be produced.

More particularly it is my object to provide in that type of phonographs having a double sound box, improved means for transmitting vibrations from the stylus to the dia phragms of the sound boxes.

A further object is to provide a mechanism for converting mechanical Vibrations into sound waves, which is capable of being easily and quickly adjusted to produce a large variety of tone values or qualities.

My invention consists in the construction, arrangement and combination of the various parts of the device, whereby the objects contemplated are attained, as hereinafter more fully set forth, pointed out in my claims, and illustrated in the accompanying drawings, in which:

Figure 1 is a side elevation of the tone arm of a phonograph, showing the manner in which my improved mechanism is applied thereto.

Figure 2 is a plan view of the same.

Figure 3 is an enlarged detail view of the mechanism for actuating the diaphragms of the sound boxes.

Figure 4 is a detail sectional view taken on the line 44 of Figure 3.

Figure 5 is an enlarged perspective view of the stylus supporting yoke.

The numeral indicates the tone arm of a sound amplifying device 01 the usual construction, with the exception that it is smaller and is formed with a forked portion 11, so that two diverging sound tubes 12 are provided. Each of the sound tubes 12 terminate in laterally extending tubular por- ATTACHMENT 1926. Serial No. 122,246.

tions 13 which are in alinement with each other. The outer end of each of said tubular portions is formed open.

The tubular portions 13 are provided with U-shaped sound tubes 14 and 15, pivotally mounted in the members 13 and secured in position by means of set screws 16. An opening 17 is provided in each of the inner ends of the members 14 and 15 to permit communication between the U-shaped sound tubes and the diverging tubes 12. The parallel menu bers of the tube 15 are longer than those of the tube 14. The free end of the tube 15 is provided with a slidable tube 18. The tube 15 is provided with a slot 19 for receiving a pin 20 of the tube 18. The pin 20 limits the sliding movement of the tube 18 and prevents rotation of said tube relative to the tube 15. The free end of each of the tubes 14 and 18 is provided with a bayonet slot 21 in the usual manner.

Supported on each of the tubes 14 and 18 is a sound box 22. Said sound boxes are spaced apart a slight distance and rigidly supported to each other by means of transversely arranged bars 23, so that the two sound boxes are supported as a single unit. The boxes are supported in a reverse manner so that diaphragms 24 face each other. The said diaphragms and boxes are of the usual construction. The boxes are secured to the tubular members 14 and 18 by bayonet pins 25, which may be detached by simply rotating the sound boxes so that the pins 25 enter the longitudinal portions of the grooves 21, after which the tube 18 may be moved outwardly, causing it to disengage its corresponding sound box, after which the sound boxes may be moved toward the tube 15 ant disengaged from the tube 14. The tube 18 is moved outwardly until its free edge is substantially in alinement with the free end of the tube 15, which will permit the sound boxes to be moved laterally from between the free ends of the tubes 14 and 18.

Each of the sound boxes 22 is provided with the usual stylus bar 26, having its inner end connected rigidly to a link 27. The ends of sai'ddinks connect the central portions of the diaphragms 24. Each of the stylus bars 26 is provided with the usual stylus clamping socket 28 and set screws 29. For connecting both of these sockets 28 with a single stylus, I have provided a yoke bar 30, each end of which is provided with a laterally extending pin 31. The pins 31 are designed to enter the sockets 28 and to be rigidly locked therein by means of set screws 29. The central portion of the yoke bar is provided with an opening 32 for receiving the stylus 33, which is locked in position by means of a set screw 34.

To provide means whereby the stylus arms maybe yieldably supported to their respective sound boxes, I have provided in each sound box 22 an outwar ly projecting pin 35, each designed to support a pivot 36 of the said stylus bars. The said pivots are provided with flattened surfaces 37, each of which has a notch 38 for resting against the point of the pins 35. The pivots 36 are yieldably retained in position by means of springs 39. These pivot members on the standard sound boxes are intended to permit pivotal action of the stylus bar, but when my improvement 7 has been applied the inner ends of the stylus bars are connected to the link 27 while the outer ends, or socket portions, of said bars are rigidly connected to the yoke 30, so that the oscillating movement of the stylus bars is considerably reduced and modified on account of the stillness of the connections between the yoke and link.

tubular member 14.

It will be seen that if the stylus 33 is placed on a record, with its point in the groove of said record, and the record rotated, then the point otthe stylus will be oscillated transversely which willcause the bar 30 to be oscillated transversely, and transd verse movement applied to the members 26,

which in turn imparts. longitudinal movement to the link 27, causing the diaphragms 24 to be oscillated, one of the diaphragms being moved inwardly while the other is moved outwardly, and thereby producing tones of somewhat lighter volume than those produced by the ordinary single-diaphragms, and which are in turn of very high quality and clear, representingn'iore closely the natural tones of the original instruments or voices.

It will be seen that the Ushaped tubular member 15 is considerably longer than the This is for the purpose of: permitting the sound box to be removed without disconnecting the pivotal ends of either of said tubes, and also for the'purpose of providing a longer sound passage on one side than the other. This has a tendency to throw the sound waves of he longer passage slightly out of phase or behind those of the shorter passage, thereby increasing the resonance of the tone, as it is a well known fact that it sound waves can be split into various phases, which are slightly out of time, then the resonance of the tone is increased.

I have found by actual experiment that various tone qualities may be provided by forming the yoke 30 of various kinds of metal. The length of the pins 31 also may be varied to give lighter or stronger tones. The tone qualities will also be varied by lengthening and shortening said pins.

A single sound box may be operated if so desired by simply removing the yoke 30 and placing the stylus in one of the sockets 28, and the device may then be operated in the usual manner, or if modification is desired, one of the tubular members 15 may be detached from the sound box, which is provided with no stylus.

Thus it will be seen that I have provided a, attachment for phonographs, which is comparatively inexpensive to manufacture, inasmuc as the standard parts of the sound box are utilized in my construction. The device when constructed may be used to get a large number of tone effects with a very small change in the apparatus, and when used as illustrated in Figures 2 and 3, will produce a clear tone or" high quality.

I claim my invention:

1. A phonograph attachment comprising a tone arm having its receiving end terminating in diverging tubular portions, a U-shapcd tone tube pivotally mounted in each of the diverging arms, the free ends of said tubes being spaced apart and in alinement with each other, one of said tubes being longer than the other and having its free end shortened, a tube slidably mounted in the shortened end, and means for connecting the free end of the first said tube and the said slidable tube to a sound box.

2. A phonograph attachment comprising a tone arm having its receiving end terlni nating in diverging tubular portions, a U- shaped tone tube pivotally mounted in each of the diverging arms, the free ends of said tubes being spaced apart and in alinement with each other, one of said tubes being longer than the other and having its free end shortened, a tube slidably mounted in the shortened end, means for connecting the free end of the first said tube and the said slidable tube to a sound box, and means for limiting the movement of the slidable tube.

Des Moines, Iowa, December 8, 1927.

ULYSSES J. BURKE. 

